Over a hundred years ago, in 1904, the chief forester Herman Merkel of New York Zoological Park grew concerned as the American chestnut trees under his watch were dying off. Chestnut blight had entered the United States. It is caused by a rapidly spreading airborne fungus, which was accidentally introduced with imported Asian chestnut trees. Then, in just a few decades of biological blitzkrieg, the blight decimated billions of chestnut trees across the entire eastern Northern America. The American chestnut, an iconic tree once essential both ecologically and economically now stand completely devastated. Only a few isolated patches of full grown American chestnut trees remain today, mostly in areas outside their historical range.
But American chestnut is not extinct. In many places, former trees keep producing small sprouts from their stumps. The sprouts grow into trees but die off once the blight returns. So the challenge is to find a blight-resistant American chestnut. Many organizations, including American Chestnut Foundation, have taken on this challenge and determinedly work towards the restoration of American chestnut. After all, the Asian chestnut, a close relative, has a naturally developed resistance to the fungus so developing a blight-resistant variety of the American cousin seems feasible in principle.
The restoration efforts have relied on conventional breeding approaches, but we can now add some new heavy weaponry—genetic bioengineering—to the potential arsenal. This new option was discussed at the inaugural 60th Anniversary series of lectures at Resources for the Future, on Wednesday October 3rd, by a panel of experts associated with the Forest Health Initiative (FHI). Over the last three years, FHI has scrutinized the potential of using genetic bioengineering to restore the American chestnut. The initial goal of the initiative is to develop a genetically modified (GM) tree, which is resistant to blight, socially acceptable, economically feasible, and meets regulatory muster. In the world of bioengineering, these may come off as lofty goals, but the panelists explained FHI is not only serious about them but also making substantial progress in all fronts.
Of course, bioengineering is not entirely new in forestry, although it has progressed at a slower pace than in agriculture. For example, two years ago, federal regulators approved a permit to ArborGen, a biotech company, to move ahead with the field trials of eucalyptus trees genetically modified for improved cold resistance (see the story in New York Times). Additionally, FDA approved for commercial purposes two fruit trees, papaya in 1997 and plum in 2009), genetically modified to resist harmful viruses.
While the potential for bioengineering is massive, it also creates serious concerns. These concerns are similar in the context of trees and forests as relative to agriculture and GM crops. The long life-cycle of trees further amplifies the concerns; while GM crops are around for a growing season, forests stick around for tens of years and create more opportunities for mixing the natural varieties. While genetically modified organisms are often also modified not to reproduce naturally, the opponents fear that fully preventing the spread of the modified genes is difficult in practice and the risk of genetic contamination of naturally occurring varieties is high. A report from the International Union for Conservation of Nature discusses this and other risks associated with genetically modified organisms. Economic and social considerations of commercialized genetically modified forests can also be complex; they are examined by RFF Senior Fellow Roger Sedjo in a RFF Discussion paper.
Returning back to the Forest Health Initiative, it prides itself by being markedly different from the commercial development of bioengineered trees. For one thing, FHI is non-commercial and intended to provide information freely available in public domain. The panelists also stressed that FHI is working towards evaluating, not promoting, the potential use of genetic bioengineering in restoring the American chestnut and, more generally, protecting American forests. Acknowledging that the issue is not only about engineering, the group uses a “braided” approach, which seeks to comprehensively combine information from analyses and stakeholder engagements in all areas critical to the effort, including biological, policy, social and environmental areas.
Over the course of three years—lighting fast by most standards—FHI has not only mapped the genome of the American chestnut but also developed a genetically modified, fungus-resistant American chestnut which is nearing readiness for field trials. If successful, the tree could help re-introduce American chestnut where it once flourished. Of course, the ecosystems have gone through radical changes since the disappearance of the chestnut and will never be restored to what they once were. Regardless, the potential change could appear attractive to many. Just imagine that by genetically tweaking just one aspect of the American chestnut, one might protect the trees from falling victims to an invasive and accidentally imported fungus. Unlike conventional breeding approaches, genetic bioengineering could more easily leave the rest of the tree unchanged. The trees would also be able to reproduce naturally.
But would the genetically modified American chestnut really be like the original, just a bit tougher? Will the ecosystems function as they once did, or would unexpected and unintended harmful consequences emerge? Much work remains ahead to answer these questions. And while biological, ecological, and regulatory aspects may be possible to be worked out, how would the American public react? Will it approve or fear the new old tree? This will be an interesting and important effort in the years to come.
For more information, tune into the recorded web-cast of the event.